Catalyst for oxidation of isobutylene

Abstract

A catalyst for oxidation of isobutylene which has a composition of the general formula Mo.sub.a Bi.sub.b Fe.sub.c Co.sub.d Ni.sub.e P.sub.f Pb.sub.g X.sub.h O i wherein X is at least one alkali metal element selected from K, Rb and Cs; a, b, c, d, e, f, g and h respectively represent the number of Mo, Bi, Fe, Co, Ni, P, Pb and X atoms, and when a is 12, b is 0.1-10, c is 9-20, d is 0-12, e is 0-12 with the proviso that the sum of d and e is 0.5-15, f is 0.1-5, g is 0.05-8 and h is 0.01-5; and i is the number of oxygen atoms which satisfies the atomic valences of the other elements.

What we claim is: 
     
       1. A process for preparing methacrolein which comprises oxidizing isobutylene with molecular oxygen in the vapor phase at a temperature of 250° to 700° C. in the presence of a catalyst which has a composition of the formula   Mo.sub.a Bi.sub.b Fe.sub.c Co.sub.d Ni.sub.e P.sub.f Pb.sub.g X.sub.h O.sub.i     wherein X is at least one alkali metal element selected from the group consisting of K, Rb and Cs; a, b, c, d, e, f, g and h respectively represent the number of Mo, Bi, Fe, Co, Ni, P, Pb and X atoms, and a is 12, b is 0.1-10, c is 9-20, d is 0-12, e is 0-12 with the proviso that the sum of d and e is 0.5-15, f is 0.1-5, g is 0.05-8 and h is 0.01-5; and i is the number of oxygen atoms which satisfies the atomic valences of the other elements.   
     
     
       2. The process of claim 1 wherein a is 12, b is 0.5-7, c is 10-15, d is 0-10, e is 0-10 with the proviso that the sum of d and e is 0.5-12, f is 0.1-4, g is 0.1-4 and h is 0.01-4. 
     
     
       3. The process of claim 1 wherein R is K. 
     
     
       4. The process of claim 1 wherein R is Rb. 
     
     
       5. The process of claim 1 wherein R is Cs. 
     
     
       6. The process of claim 1 wherein air is used as a source of oxygen. 
     
     
       7. The process of claim 1 wherein the reaction is carried out in the presence of an inert gas. 
     
     
       8. The process of claim 1 wherein the reaction is carried out at a temperature of 250° to 550° C.